Method and apparatus for monitoring of component housing wall thickness and wear monitoring

ABSTRACT

A method for monitoring wall thickness of an industrial piping component or pump/fluid machinery, including a pump casing for a pump used for pumping an abrasive fluid or slurry, comprising providing a signal containing information about a ultrasonic-based transducer pulse from a discrete ultrasonic-based transducer attached directly on an industrial piping component or pump/fluid machinery at a local point of interest and configured to inject the ultrasonic-based transducer pulse into the industrial piping component or pump/fluid machinery at the local point of interest and sense the ultrasonic-based transducer pulse reflected off a wall of the industrial piping component or pump/fluid machinery at the local point of interest; and determining with an electronic monitoring system the thickness of the wall of the industrial piping component or pump/fluid machinery at the local point of interest based at least partly on the signal received containing information about the discrete ultrasonic-based transducer pulse sensed. The discrete ultrasonic-based transducer may include a discrete ultrasonic-based piezoelectric transducer.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application corresponds to international patent application serial no. PCT/US2011/28957, filed 18 Mar. 2011.

The corresponding international patent application serial no. PCT/US2011/28957 claims benefit to provisional patent application Ser. No. 61/315,233, filed 18 Mar. 2010 (WFVA/CiDRA nos. 712-2.342/CCS-0038) and is a continuation-in-part of patent application Ser. No. 12/922,261, filed 30 Nov. 2010 (712-2.319-1/CCS-0022).

That parent patent application Ser. No. 12/992,261 (712-2.319-1/CCS-0022) is a national stage application and corresponds to PCT/US2009/037269, filed 16 Mar. 2009 (herein after the “269 PCT patent application”). The corresponding '269 PCT patent application claims benefit to provisional patent application Ser. No. 61/133,878, filed Jul. 2, 2008 (CCS-0001); Ser. No. 61/103,686, filed Oct. 8, 2008 (CCS-0005); Ser. No. 61/117,762, filed Nov. 25, 2008 (CCS-0010); Ser. No. 61/036,689, filed Mar. 14, 2008; and Ser. No. 61/054,612, filed May 20, 2008 (CCS-0023), which are all incorporated by reference in their entirety.

BACKGROUND OF THE INVENTION

1. Field of Invention

This invention relates to a technique for non-invasive and real-time measurement and monitoring of a wall thickness of an industrial piping component or pump fluid machinery having a media flowing therein.

This invention also relates to a technique for monitoring trends in the wear of walls of an industrial piping component or pump fluid machinery.

More particularly, this invention also related to using these techniques in relation to media such as an abrasive fluid or a slurry.

2. Description of Related Art

Historically, flow measurements in the mineral processing industry have suffered from the limitations of previously available flow meter technology including commonly used instruments such as ultrasonic meters, electromagnetic meters, turbine meters, orifice plate meters, vortex flow meters, Coriolis meters, and Venturi meters. Sonar array flow measurement technology, which entered the mineral processing industry a few years ago, has overcome many of these limitations. The development of this technology began with the specific goal of non-invasively measuring multi-phase flows in the petroleum industry. The same technology was later adapted to the mineral processing industry where it has experienced rapid adoption.

By way of example, there has been a long history of using ultrasonics based nondestructive testing to determine the wall thickness of metallic pipes. To date this method of determining wall thicknesses has been costly, unreliable, and of limited use for trending wear rates.

In view of this, there is a need in the industry to reduce the high labor costs associated with the known method and to decrease the variance found in these manually performed measurements.

SUMMARY OF THE INVENTION

The present invention provides new techniques for monitoring wall thickness of an industrial piping component or pump/fluid machinery, including a pump casing for a pump used for pumping an abrasive fluid or slurry.

The present invention may take the form of a method comprising: providing a signal containing information about a ultrasonic-based transducer pulse from a discrete ultrasonic-based transducer attached directly on an industrial piping component or pump/fluid machinery at a local point of interest and configured to inject the ultrasonic-based transducer pulse into the industrial piping component or pump/fluid machinery at the local point of interest and sense the ultrasonic-based transducer pulse reflected off a wall of the industrial piping component or pump/fluid machinery at the local point of interest; and determining with an electronic monitoring system the thickness of the wall of the industrial piping component or pump/fluid machinery at the local point of interest based at least partly on the signal received containing information about the discrete ultrasonic-based transducer pulse sensed.

The method may also include one or more of the following features: The method may include directly attaching the discrete ultrasonic-based transducer on the industrial piping component or pump/fluid machinery at the local point of interest, as well as injecting the ultrasonic-based transducer pulse into the industrial piping component or pump/fluid machinery at the local point of interest and sensing the ultrasonic-based transducer pulse reflected off the wall of the industrial piping component or pump/fluid machinery at the local point of interest. The method may include providing a plurality of signals from a respective plurality of discrete ultrasonic-based piezoelectric transducers, each discrete ultrasonic-based piezoelectric transducer attached directly on the industrial piping component or pump/fluid machinery at a respective local point of interest. The method may include providing an indication from the electronic monitoring system containing information about the thickness of the wall of the industrial piping component or pump/fluid machinery at the local point of interest, including an output signal, an audio indication, a visual indication, or some combination thereof. The plurality of signals from the respective plurality of discrete ultrasonic-based piezoelectric transducers to the electronic monitoring system via a wiring harness. The discrete ultrasonic-based transducer may be housed in a lightweight, low profile, small footprint package so as to be positionable into a tight space and into a local area for measurement, including the lightweight, low profile, small footprint package being dimensioned to include a length of about 3″, a width of about 1.5″ and a height of about 0.8″. The method may include coupling the discrete ultrasonic-based transducer to iron components by high-strength permanent magnets and a suitable ultrasonic coupling gel, which allows easy installation, removal and repositioning of the discrete ultrasonic-based transducer, and also allows the discrete ultrasonic-based transducer to be adjusted to maximize signal strength and quickly redeployed to other wear points of interest. The method may also include coupling the discrete ultrasonic-based transducer to a substrate using a pressure sensitive adhesive or a dispensable adhesive. The discrete ultrasonic-based transducer may comprise a discrete ultrasonic-based piezoelectric transducer made at least partly from PVDF material or one or more separate and individually distinct piezoelectric transducer elements.

The present invention may take the form of a system for monitoring wall thickness of an industrial piping component or pump/fluid machinery, including a pump casing for a pump used for pumping abrasive fluids or slurry, comprising a plurality of discrete ultrasonic-based transducers, an electronic monitoring system and a wiring harness for coupling the plurality of discrete ultrasonic-based transducers to the electronic monitoring system. Each of the plurality of discrete ultrasonic-based transducers may be configured to be attached directly on the industrial piping component or pump/fluid machinery at a respective local point of interest. Each of the plurality of discrete ultrasonic-based transducers may also be configured to provide a respective signal containing information about a respective ultrasonic-based transducer pulse injected into the industrial piping component or pump/fluid machinery at the local point of interest and sensed after the ultrasonic-based transducer pulse is reflected off a wall of the industrial piping component or pump/fluid machinery at the local point of interest. The electronic monitoring system may be configured to receive respective signals from the plurality of discrete ultrasonic-based transducers, and determine the thickness of the wall of the industrial piping component or pump/fluid machinery at the respective local points of interest based at least partly on the respective signals received.

The system may include one or more of the following features: The electronic monitoring system may be configured to provide an indication containing information about the thickness of the wall of the industrial piping component or pump/fluid machinery at the local point of interest, including an output signal, an audio indication, a visual indication, or some combination thereof. Each discrete ultrasonic-based transducer may be housed in a lightweight, low profile, small footprint package so as to be positionable into a tight space and into a local area for measurement, including where the lightweight, low profile, small footprint package is dimensioned to include a length of about 3″, a width of about 1.5″ and a height of about 0.8″. The system may include high-strength permanent magnets and a suitable ultrasonic coupling gel for coupling the discrete ultrasonic-based transducer to iron components so as to allow easy installation, removal and repositioning of the discrete ultrasonic-based transducer, and also allow the discrete ultrasonic-based transducer to be adjusted to maximize signal strength and quickly redeployed to other wear points of interest. The system may include a pressure sensitive adhesive or a dispensable adhesive for coupling the discrete ultrasonic-based transducer to a substrate. The discrete ultrasonic-based piezoelectric transducer may comprise a discrete ultrasonic-based piezoelectric transducer made at least partly from PVDF material or one or more separate and individually distinct piezoelectric transducer elements.

The present invention may take the form of apparatus, including a signal processor configured to: receive a signal containing information about a discrete ultrasonic-based transducer pulse that is injected by a discrete ultrasonic-based transducer attached directly to a discrete location of an industrial piping component or pump/fluid machinery and sensed by the discrete ultrasonic-based transducer after being reflected off a surface of a wall of the industrial piping component or pump/fluid machinery; and determine the thickness of the wall of industrial piping component or pump/fluid machinery at the discrete location based at least partly on the signal received.

The signal processor may form part of an electronic monitoring system configured to monitor the thickness of the wall of the discrete location of the industrial piping component or pump/fluid machinery at the discrete location, including providing an output signal containing information about the thickness of the wall of the industrial piping component or pump/fluid machinery at the discrete location. The electronic monitoring system may be configured to provide an indication containing information about the thickness of the wall of the industrial piping component or pump/fluid machinery at the local point of interest, including an output signal, an audio indication, a visual indication, or some combination thereof. The discrete ultrasonic-based piezoelectric transducer may comprise a discrete ultrasonic-based piezoelectric transducer made at least partly from PVDF material. Each discrete ultrasonic-based transducer may also be housed in a lightweight, low profile, small footprint package so as to be positionable into tight spaces and into local areas for measurement.

According to some embodiments, the present invention may take the form of apparatus comprising means for receiving a signal containing information about a discrete ultrasonic-based transducer pulse that is injected by a discrete ultrasonic-based transducer attached directly to a discrete location of an industrial piping component or pump/fluid machinery and sensed by the discrete ultrasonic-based transducer after being reflected off a surface of a wall of the industrial piping component or pump/fluid machinery; and means for determining the thickness of the wall of industrial piping component or pump/fluid machinery at the discrete location based at least partly on the signal received, consistent with that shown and described herein. The apparatus may further comprise means for providing an indication, in the form of an output signal, an audio indication, a visual indication, or some combination thereof, containing information about the thickness of the wall of the industrial piping component or pump/fluid machinery at the local point of interest.

BRIEF DESCRIPTION OF THE DRAWING

The drawing includes FIGS. 1a -33, which are not drawn to scale, as follows:

FIG. 1a shows a system that includes a plurality of discrete ultrasonic-based piezoelectric transducers and an electronic monitoring system, according to some embodiments of the present invention.

FIG. 1b shows a plurality of discrete ultrasonic-based piezoelectric transducers attached directly on a pump casing for a pump used for pumping an abrasive fluid or slurry, according to some embodiments of the present invention.

FIG. 1c shows a top view of a discrete ultrasonic-based piezoelectric transducer, according to some embodiments of the present invention.

FIG. 1d shows a bottom view of the discrete ultrasonic-based piezoelectric transducer shown in FIG. 1c , according to some embodiments of the present invention.

FIG. 2a is a cutaway of a pipe under a sonar array sensor band illustrating turbulent eddies.

FIG. 2b is an illustration of a signal detected by passive sensors in an array from one collection of turbulent eddies.

FIG. 3, including FIGS. 3a, 3b, 3c and 3d , shows various flows in a pipe, including homogeneous flow (FIG. 3a ); heterogeneous flow with full suspended particles (FIG. 3b ); heterogeneous flow with moving bed (FIG. 3c ); and heterogeneous flow with stationary bed (FIG. 3d ).

FIG. 4 is a diagram of a slurry test loop setup.

FIG. 5 is a graph of velocity (m/s) and density gauge (kg/m³) versus time (hrs:min:sec) showing a velocity profile of an 89 micron mining slurry.

FIG. 6 is a graph of velocity (m/s), and alarm state and density gauge (kg/m³), versus time (hrs:min:sec) showing an alarm state of an 89 micron mining slurry.

FIG. 7 includes two graphs, including FIG. 7a showing a graph of height (diameters) versus a normalized velocity for mostly homogeneous flow, suspended particles, and FIG. 7b showing a graph of height (diameters) versus a normalized velocity for mostly heterogeneous flow with suspended particles.

FIG. 8 showing a graph of height (diameters) versus a normalized velocity for a heterogeneous flow with a stationary solids bed.

FIG. 9 is a graph of flow velocity (m/s) and density (kg/m³) versus time (hrs:min:sec) showing 186 micron slurry solid deposition detected by sonar meter, densitometer, and delta-pressure.

FIG. 10 is a graph of normalized height (diameter) in relation to flow (m/s) showing velocity profiles versus a reference velocity.

FIG. 11 is a graph of three-dimensional velocity profiles and velocity contours in an inhomogeneous flow.

FIG. 12, including FIGS. 12a and 12b , is an illustration of a velocity profile monitoring system in operation at a site.

FIG. 13 is a graph of velocity (f/s) and sanding factor versus time (hrs:min:sec) showing the detection of a sand bed and development of a sand bed in a slurry pipeline in the field.

FIG. 14 is a graph of velocity (f/s) versus time (hrs:min:sec) showing the detection of water flush (no stratification) and a sand bed deposition in a slurry pipeline in the field.

FIG. 15a is an illustration of a system in operation at a site, and FIG. 15b is an illustration of a conceptual layout of a system; and FIG. 15c is a block diagram of an ultrasonic pulser/receiver and signal processor according to the present invention.

FIG. 16 is an illustration of a comparison of pipe wall thickness measurement points according to the present invention and a conventional technique.

FIG. 17 is a graph of pipe wall thickness (mm) versus an angular position (degrees) from the top showing a conventional ultrasonic pipe wall thickness measurement versus a measurement according to the present invention.

FIG. 18 includes FIG. 18a which is a graph of pipe wall thickness (mm) versus an angular position (degrees) from the top showing a measurement according to the present invention, and FIG. 18b which is a view of a pipe profile with the data in FIG. 18 a.

FIG. 19 is a graph of percentage of occurrence (%) versus a repeatability variation (%) showing a small spread in data over 90 C temperature range and over three sensors.

FIG. 20 is a graph of wall thickness (mm) versus position on pipe (angle from the top according to initial installation) showing a measurement of the pipe wall thickness as a function of angular position and time.

FIG. 21, including FIGS. 21a, 21b and 21c , show inner surface irregularities seen on a chromium-steel worn pipe.

FIG. 22 shows two graphs showing the impart of temperature cycling on wall thickness measurement and signal amplitude (−40 C to +40 C with 10 hour hold), including FIG. 22a which is a graph of pipe wall thickness (mm) versus time (days), where times t₁, t₂, t₃, t₄ are about 25 days apart, and FIG. 22b which is a graph of signal level versus microseconds.

FIG. 23 is a graph of signal amplitude versus time showing long term high temperature testing, having signal amplitude graphs for times t₁, t₂, t₃, where time t₂ is about one month after time t₁, and where time t₃ is about three months after time t₁.

FIG. 24 is an illustration of a pipe having a sensor according to the present invention.

FIG. 25, including FIGS. 25a and 25b , shows two embodiments of the present invention having an optional spacer arranged between the pipe wall.

FIG. 26 is a graph of signal amplitude versus time of a pulse injected into a pipe wall and bouncing back-and-forth.

FIG. 27, including FIGS. 27a and 27b , shows embodiments of the present invention using a traditional ultrasonic transducer and a PVDF large area ultrasonic transducer.

FIG. 28, including FIGS. 28a and 28b , shows embodiments of the present invention using either a couplant between a pipe wall and a PDVF sensor, or a compliant backing material between the PDVF sensor and a band, or a combination thereof.

FIG. 29, including FIGS. 29a and 29b , includes graphs in polar coordinates of a pipeline and an underflow pipe showing pipe wall thickness (mm) as a function of angular position from the top of the pipe on two different pipes.

FIG. 30 shows measurements of 12 points around a wall of a pipe that can be used to interpolate measurement data at points in-between.

FIG. 31 is a graph of a measured wall thickness versus angular position about a pipe, showing a case where measured wall thickness cannot be described by a set of limited Fourier components.

FIG. 32 is a graph of a wear rate (mm/day) versus degrees from a sensor showing a calculated wear model for a pipe.

FIG. 33 is a diagram of a path of a an ultrasonic signal through the material of a pipe wall.

FIG. 34 shows an embodiment in which an orientation or rotation sensor is integrated into a sensor board along with the pipe wall thickness measurement devices.

DETAILED DESCRIPTION OF BEST MODE OF THE INVENTION

The '269 PCT patent application, to which this application claims benefit above, discloses the measurement and trending of pipe wear on slurry lines. In contrast to known manual methods, the '269 patent application discloses the use of a permanently or semi-permanently installed ring of conformable ultrasonic transducers clamped onto the outside of the pipe. By way of example, see FIGS. 2b, 15b , 24, 34. These transducers are used to measure the thickness of the pipe under their respective locations. This results in better repeatability, accuracy, and failure prediction, along with reduced labor costs. The benefit is significantly improved pipe wear monitoring in pipelines with abrasive solids. This provides an improvement in the ability to insure safe operation and avoidance of costly operational and environmental damage due to leaks caused by pipe wear. The specific sensor technology, based on piezoelectric film sensors, provides unique measurement capabilities.

The present invention utilizes the benefits of the ultrasonic transducers disclosed in the '269 PCT patent application to monitor the thickness of various industrial piping components and pump/fluid machinery, such as a pump casing 2 a for a pump 2 (FIG. 1b ) used for pumping an abrasive fluid or slurry.

The present invention consists of a combination that includes a number of discrete ultrasonic-based transducers/sensors 4 and an electronic monitoring system 6 to measure the thickness of the wall of the industrial piping components and pump/fluid machinery, such as the pump 2. The transducers/sensors 4 can be arrayed at one or more local points of interest as shown on a fluid conveying component subjected to wear and failure from abrasive fluids and slurries. FIG. 1a shows the discrete ultrasonic-based transducers/sensors 4 and the electronic monitoring system 6 that form part of the system.

In FIG. 1b , the transducers/sensors 4 are shown positioned on the pump casing 2 a for monitoring the wear of the pump casing 2 a at local points of interest. In FIG. 1b , the transducers/sensors 4 are attached directly to the pump casing 2 a for monitoring the thickness of the wall of the pump casing 2 a at the local points of interest. Each of the transducers/sensors 4 are attached through, e.g., a harness 8, to electronic monitoring system or instrumentation 6.

In FIGS. 1c, 1d , each of the transducers/sensors 4 are housed in a lightweight, low profile, small footprint package (3″L×1.5″W×0.8″T) to allow it to be positioned into tight spaces and into local areas for measurements. In some embodiments, the transducers/sensors 4 may be coupled to iron components by one or more high-strength permanent magnets 4 c and a suitable ultrasonic coupling gel (not shown), which allow easy installation, removal, and repositioning. This also allows for transducers/sensors 4 to be adjusted to maximize signal strength or quickly redeployed to other wear points of interest. Ultrasonic coupling gels are known in the art and the scope of the invention is not intended to be limited to any particular type or kind either now known or later developed in the future.

The transducers/sensors 4 may also include a sensor housing 4 a, an I/O connector 4 b, a foam rubber interface pad 4 d and an ultrasonic sensor portion 4 e. In operation, the transducers/sensors 4 is configured to inject an ultrasonic-based piezoelectric pulse into the industrial piping components and pump/fluid machinery 2 at a local point of interest, and sense the ultrasonic-based piezoelectric pulse reflected off a wall of the industrial piping components and pump/fluid machinery 2 at the local point of interest. In FIG. 1b , the industrial piping components and pump/fluid machinery is shown as the pump 2, although the scope of the invention is intended to include other types or kind of industrial piping components and pump/fluid machinery either now known or later developed on the future. The electronic monitoring system or instrumentation 6 is configured to determine the thickness of the wall of the industrial piping component or pump/fluid machinery 2 at the local point of interest based at least partly on the signal received containing information about the discrete ultrasonic-based piezoelectric transducer pulse sensed.

Other embodiments are also envisioned in which, e.g., if a more permanent installation is desired, and if surface finishes allow, then the transducers/sensors 4 can also be coupled to any substrate using pressure sensitive adhesives (PSA's), not shown, or a dispensable adhesive (not shown). On suitable components, the magnetic coupling can be used for temporary positional testing or clamping duties to allow dispensed adhesives to cure in place. Moreover, the scope of the invention is intended to include the transducers/sensors 4 being permanently attached, e.g., by suitable glue, or removably attached, e.g., by magnetic coupling or by screws or other suitable fasteners for directly attaching the transducers/sensors 4 to, e.g., the pump casing.

Ultrasonic-based transducers, such as ultrasonic-based piezoelectric transducers, are known in the art, and the scope of the invention is not intended to be limited to any particular type or kind either now known or later developed in the future for implementing the present invention within the spirit of that disclosed herein. For example, the scope of the invention is not intended to be limited to only using ultrasonic-based piezoelectric transducers.

The electronic monitoring system or instrumentation 6 may be implemented using the signal processing technology consistent with that shown and described herein. By way of example, and consistent with that described herein, the functionality of the electronic monitoring system or instrumentation 6 may be implemented using hardware, software, firmware, or a combination thereof, although the scope of the invention is not intended to be limited to any particular embodiment thereof. In a typical software implementation, the electronic monitoring system or instrumentation 6 would be one or more microprocessor-based architectures having a microprocessor, a random access memory (RAM), a read only memory (ROM), input/output devices and control, data and address buses connecting the same. A person skilled in the art would be able to program such a microprocessor-based implementation to perform the functionality described herein without undue experimentation. The scope of the invention is not intended to be limited to any particular implementation using technology now known or later developed in the future. Moreover, the scope of the invention is intended to include the electronic monitoring system or instrumentation 6 being a stand alone module, as shown, or in the combination with other circuitry for implementing another module.

The electronic monitoring system 6 may be configured to provide an indication containing information about the thickness of the wall of the industrial piping component or pump/fluid machinery at the local point of interest, including an output signal, an audio indication, a visual indication, or some combination thereof. By way of example, the indication may take the form of a visualization of the wall thickness of the pump casing 2 a of the pump 2, consistent with that shown in FIG. 18 herein, or a visualization of the measurement of the wall thickness as a function of angular position and time as shown in FIG. 20 herein. The indication may be provided on a video screen or display that forms part of the electronic monitoring system 6, or a video screen or display that is remotely located and receives such an output signal containing information about the wall thickness, or both.

The remainder of this application discloses the technique set forth in the continuation-in-part of patent application Ser. No. 12/922,261, filed 13 Sep. 2010, which is related to the '269 PCT patent application.

I. FIGS. 2a -14: Non-Invasive Velocity Profile Measurement

Principle of Operation for Passive Array Based Flow Measurement Using Sonar Processing Algorithms

Sonar array-based meters track and measure the mean velocities of coherent disturbances traveling in the axial direction of a pipe. These disturbances can take many different forms and can propagate at different velocities. Their propagation method and velocities include convection with the flow (slowest velocity-fluid flow), propagation in the fluid or slurry (mid-range velocity-acoustics), and propagation in the pipe walls (fast velocity-vibrations). The sonar array-based meters discriminate between the three main propagation modes through a combination of frequency and velocity differences.

First, the description focuses on the disturbances that convect with the flow. These disturbances can be density variations, temperature variations, turbulent eddies, or others. Within most industrial processes, the most common flow disturbance is turbulence. Turbulent eddies, or vortices, are naturally present in flow regimes where Reynolds numbers are greater than 4000. The Reynolds number represent the ratio of inertial forces to viscous forces and numbers greater than 4000 are said to be turbulent and less than 2300 are considered to be laminar. The larger the Reynolds number, the broader the range of turbulent eddies within the flow. The fundamental principle of sonar flow measurement is based on tracking these turbulent eddies as they pass through an array of sensors (Gysling, D. and Mueller, E., (2004). Application of Sonar-Based Clamp-On Flow Measurement in Oils and Processing. ISA 2004 Exhibit and Conference). A cutaway illustration of these turbulent eddies within a pipe under a sonar array sensor band is shown in FIG. 2 a.

Through the combination of an array of passive sensors and the sonar array processing algorithms, the average axial velocities of a collection of vortices is obtained. The sequence of events that occur to make this measurement possible is as follows:

-   -   As these turbulent eddies pass by any fixed location on the         pipe, they will exert a small dynamic stress on the inside of         the pipe wall     -   The strain induced in the pipe wall from these dynamic stress         fluctuations is converted to an electrical signal through a         passive sensor wrapped partially or fully around the pipe (FIG.         2 exaggerates)—no couplant gels or liquids are required since         these are low frequency mechanical strains and not ultrasonics     -   The unique electrical signal from each collection of turbulent         eddies is detected by each element of the array of sensors.         These sensors are spaced a precisely set distance from each         other along the axial direction of the pipe.     -   The separation between sensors in the array is shorter than the         coherence length of the turbulent eddies, thereby resulting in         similar voltage signatures from each sensor in the array with         only a delay in time. When sonar array processing is applied to         the output signals of the array, the velocity at which these         turbulent eddies pass through the array of sensors is         determined, thus providing the propagation speed of the fluid         within the pipe (Nelson, R. O., (2001). Sonar Signal Processing,         Artech House Inc., Norwood, Mass., USA, ISBN 0-89006-453-9).

This process is illustrated with one collection of turbulent eddies in FIG. 2b , but in practice is applied to numerous collections of turbulent eddies. In FIG. 2, the apparatus or system, generally indicated as 10, features a sensor array 12 arranged in relation to a pipe 14; amplifiers and digitizers 16 that receive sensor array signalling containing information about coherent disturbances 14 a of a media flowing in the pipe 14, and amplifier and digitizer the sensor array signalling; and one or more modules 18 configured to respond to signalling containing information about coherent disturbances 14 a and to provide a corresponding signal along line 18 a containing information about a measurement of a velocity profile of the media flowing in the pipe.

By way of example, and consistent with that described herein, the functionality of the one or more modules 18 may be implemented using hardware, software, firmware, or a combination thereof, although the scope of the invention is not intended to be limited to any particular embodiment thereof. In a typical software implementation, the one or more modules 18 would be one or more microprocessor-based architectures having a microprocessor, a random access memory (RAM), a read only memory (ROM), input/output devices and control, data and address buses connecting the same. A person skilled in the art would be able to program such a microprocessor-based implementation to perform the functionality described herein without undue experimentation. The scope of the invention is not intended to be limited to any particular implementation using technology now known or later developed in the future. Moreover, the scope of the invention is intended to include the one or more modules 18 being a stand alone module, as shown, or in the combination with other circuitry for implementing another module. Moreover, the real-time part may be implemented in hardware, while non real-time part may be done in software.

Velocity Profile in Horizontal Pipelines

In mining and oil sands applications a vast majority of product and tailings transport is done as slurry. Flow regimes of horizontal flows can be classified into four distinct groups: homogeneous flow with fully suspended particles, heterogeneous flow with all particles suspended, flow with a moving bed, and flow with a stationary bed. (See Cheremisinoff, N. P., (1986). Encyclopedia of Fluid Mechanics. Vol. 5, Slurry Flow Technology, Golf Pub. Co.) The flow regime is dependent upon properties of the slurry such as particle size, density, flow velocity, viscosity, and particle size distribution, as well as the physical attributes of the pipeline such as diameter and surface roughness. FIG. 3 shows the particle distribution for each of these regimes.

In fully developed homogeneous liquid flows, the profile is symmetric about the pipe axis, and does not pose the danger of developing a sand bed which can potentially lead to plugging of the pipeline. In this type of flow, the profile has a radial position dependency. Few slurry flows will be purely homogeneous flows. Most slurry flows will fall into the category of heterogeneous flow with some containing the characteristics of both homogeneous and heterogeneous flow. In heterogeneous flows, there is a stratification of the solids with a higher concentration of solids at the bottom of the pipe. For the same particle size, density, viscosity, particle size distribution and physical attributes of the pipeline, the flow velocity will determine the type of heterogeneous flow, that is whether or not a sand bed has developed and the characteristics of the sand bed. In heterogeneous liquid flows, the profile is not symmetric about the pipe axis. Instead, it is symmetric about the horizontal axis but asymmetric about the vertical axis due to the vertical distribution of particles.

Sonar Array Velocity Profiling Meter

The standard clamp-on flow meter is based on using a single multiple element array which provides for a measurement of the average flow velocity in a pipe. This clamp-on technology has been extended by implementing multiple arrays located at different circumferential positions on a single band, to measure the velocity profile of the fluid. This new tool offers process operators a non-invasive measurement tool with the ability to monitor and control the profile of their process flow. The following sections summarize the results of flow loop testing and field testing performed on a sonar array profiling system and demonstrates some of the potential benefits, one of which is the ability to detect the onset of sand-out conditions. Early detection of this condition allows operators the time to apply corrective actions and avoid catastrophic process shutdown. In addition, monitoring the profile can provide useful information about the properties of the process fluid which can allow operators to adjust production variables to optimize the process.

The velocity profile meter uses arrays located circumferentially on the outside of the pipe at the top, 45 degrees from the top, on the side, 135 degrees from the top and at the bottom of the pipe. The circumferential location of the sensor arrays is shown in FIG. 5. The size of the array elements, the size of the pipe, and the circumferential location of each array on the pipe determines the vertical distance over which the flow is averaged for each array. Testing of this technology has been accomplished at several customer sites and at research facilities.

SRC Flow Loop and Test

One series of tests were conducted in a slurry test loop, shown in FIG. 4, at the Pipe Flow Technology Center of the Saskatchewan Research Council (SRC) in Canada. The scope of this test was to test slurries representative of different processes and different stages in a process. For the first slurry test an 89 m d50 particle size was selected with a mixture density of 1300 kg/m³. The second slurry test started out with a m particles. Clay and larger stones were coarser sand slurry containing 186 added subsequently to the mixture. A velocity step down test was run for each slurry type to measure the velocity profile as a function of velocity.

Slurry Test Results—89 Micron Slurry

The results of the 89 micron slurry test are graphed in FIG. 5. The velocity was stepped down in the following increments to develop a sand bed—4 m/s, 3 m/sec, 2 m/s, 1.75 m/s 1.5 m/s, 1.4 m/s, 1.3 m/s, 1.2 m/s, 1.1 m/s, 1.0 m/sec, 0.9 m/s, 0.8 m/s, and 0.7 m/s. The flow was held at each flow rate for a period of 5 minutes to allow the loop to stabilize. Continuous flow data was recorded during the entire testing time. FIG. 5 shows the step down in flow rate and the corresponding velocities measured at each of the five sensor array positions. Also shown is the output of a densitometer positioned near the bottom (y/D=0.05) of the pipe to measure solids that stratify to the bottom. To obtain a reference flow velocity, a separate flow meter was installed in an 8″ loop section where the higher flow velocity prevented solid deposition. This flow rate was then converted to an “equivalent 10 inch” velocity and graphed with the velocity profile data shown in FIG. 5.

As the flow rate is lowered the velocity profile changes to reflect the stratification changes within the pipe. It can be seen that as the flow rate decreases, the densitometer reading increases only slightly until approximately 1.5 m/s. At this velocity the density reading undergoes a step change reflecting an increase of solids at the bottom of the pipe.

Good agreement can be seen between the rapid increase in the Gamma Densitometer reading (set to measure density across the bottom of the pipe) and the relative velocities of the lower two sensors. Both indicate the formation of a bed at the same time. When the flow rate drops below the deposition velocity a bed starts to form on the bottom of the pipe and the Gamma Densitometer detects this rapid increase in density. The bottom sensor in the profile meter typically reads a lower velocity than the 135 degree sensor, due to the stratification of the slurry resulting in denser and slower moving layers near the bottom. When the bottom bed stops moving the bottom sensor detects signals from higher up in the pipe where the velocity is faster. This condition can cause the reported velocities of the bottom and 135 degree sensors to become more similar. FIG. 6 shows alarm conditions that can be generated based on the velocity differences measured by the different sensor bands. In FIGS. 7 and 8, measured velocity profiles are shown at three different flow velocities each showing three distinct flow regimes: mostly homogenous with all particles suspended (Left FIG. 7a ), heterogeneous flow with all particles suspended (Right FIG. 7b ) and heterogeneous flow with a stationary bed (FIG. 8). In the latter, the characteristic signal seen from a sand bed deposition is detected and the velocity calculated for pipe heights at the bottom and near the bottom of the pipe is set to zero.

Slurry Test Results—186 Slurry

For comparison with the previously discussed 89 micron slurry, FIG. 9 shows a step down test with the 186 micron d50 particle sized slurry. Once again, as the flow rate is lowered the velocity profile changes to reflect the stratification changes within the pipe. It can be seen that as the flow rate decreases the densitometer reading remains relatively constant at about 1600-1700 kg/m³, until at approximately 2.4 m/s it suddenly undergoes a step change reflecting an increase of solids at the bottom of the pipe. Additionally, FIG. 9 shows the pressure drop measured across the velocity profile meter, which in this case shows a sudden increase that coincides with the densitometer increase and the velocity overlaps of the bottom and 135° arrays of the velocity profile meter. Therefore the formation of the stationary solids bed was detected by the sonar velocity meter and confirmed by both the density and differential pressure measurements.

The velocity profile versus reference flow velocity is shown in FIG. 10. This plot shows that as the flow rate is reduced, two distinct changes occur to the profile. The first change is the velocity detected at the bottom of the pipe, which is the lowest velocity due to the high solids concentration. This velocity is slower relative to the velocity at the center of the pipe. Likewise, the velocities measured in the upper section of the pipe begin to move faster relative to the center of the pipe. The second change is that as the velocity is decreased further, solids are deposited on the bottom of the pipe as seen in the 1.9 m/s and 2.0 m/s flow rates.

FIG. 11 is a representation of the flow derived from the velocity profile data when coupled with flow profile models. The resulting velocity calculations in the horizontal and vertical orientations can be visualized in a three-dimensional format and through contours.

Field Implementation

A field system has been monitoring velocity profile in a slurry solution with a wide range of particle sizes. This system directly reports the flow profile and sanding condition. A picture of this system in the field is shown in FIG. 12. The multiple sensor arrays are incorporated into a single band that is placed under the cover seen in the figure. This system monitors and logs the velocity at the previously discussed circumferential positions, which can be processed to determine the conditions leading to a potential sand bed development condition. In FIG. 13, velocity and alarm states from this field system are shown. The degree of stratification and other indications are used to determine when a sand bed has developed and when a sand bed is likely to develop. The slurry being monitored has a wide distribution of sizes and as a result a high level of stratification is expected even at the relatively high flow rates experienced by this pipeline. In FIG. 14, three states can be seen, heterogeneous flow, homogenous flow during a water flush and heterogeneous flow with a sand bed.

II. FIGS. 15-33: Pipe Wall Thickness Monitoring

FIGS. 15-33 show a new technique for non-invasive pipe wall thickness monitoring. FIG. 15a shows a conceptual layout of the apparatus or system a showing a pipe P, an interface box and a protective cover; while FIG. 15b shows the apparatus or system according to the present invention generally indicated as 100 that features an ultrasonic pulser/receiver and signal processor 102 and conformable/flexible ultrasonic transducers generally indicated as 104 arranged in relation to a pipe 106 having an inner surface 108.

FIG. 15c shows a block diagram of the ultrasonic pulser/receiver and signal processor 102 having one or more modules 102 a and other modules 102 b. In operation, the one or more modules 102 a is configured to receive or respond to a signal or signalling 110 b containing information about a wave propagated through a wall 112 of the pipe 106 and to provide a corresponding signal containing information about a determination related to a thickness of the wall 112 of the pipe 106. In this case, the apparatus takes the form of a signal processor that receives or responds to the signal or signalling 110 b containing information about the wave propagated through the wall 112 of the pipe 106 from, e.g., the conformable/flexible ultrasonic transducers 104.

The corresponding signal may be provided to, e.g., to the other modules 102 b, although the scope of the invention is not intended to be limited to where or to what device the corresponding signal is provided. For example, the corresponding signal may be provided to some other modules 102 b for providing a visual indication of, e.g., either data or a graph of the thickness of the wall of the pipe. The corresponding signal may also be provided to some other circuit, module or signal processor either now known or later developed in the future, e.g. including some circuit, module or signal processor at some remote location.

In operation, the one or more modules is also configured to provide or pulse an input signal 110 a to the transducers 104, which may include an electrical input signal. However, the scope of the invention is not intended to be limited to the transducers 104 itself providing or pulsing the input signal 110 a. Embodiments are envisioned in which another device provides or pulses this input signal 110 a.

The ultrasonic pulser/receiver and signal processor 102 may take the form of a handheld unit, or may take the form of a unit attached in the physical location of the transducers 104. Embodiments are also envisioned in which the ultrasonic pulser/receiver and signal processor 102 is arranged at a remote location and receives signalling from the transducers via a hardwire connection, a wireless interface or some combination thereof. The scope of the invention is not intended to be limited to where the ultrasonic pulser/receiver and signal processor 102 is located, or how the signalling is exchanged between the transducers 104.

By way of example, and consistent with that described herein, the functionality of the one or more modules 102 a may be implemented using hardware, software, firmware, or a combination thereof, although the scope of the invention is not intended to be limited to any particular embodiment thereof. In a typical software implementation, the one or more modules 102 a would be one or more microprocessor-based architectures having a microprocessor, a random access memory (RAM), a read only memory (ROM), input/output devices and control, data and address buses connecting the same. A person skilled in the art would be able to program such a microprocessor-based implementation to perform the functionality described herein without undue experimentation. The scope of the invention is not intended to be limited to any particular implementation using technology now known or later developed in the future. Moreover, the scope of the invention is intended to include the one or more modules 18 being a stand alone module, as shown, or in the combination with other circuitry for implementing another module. Moreover, the real-time part may be implemented in hardware, while non real-time part may be done in software.

The other modules 102 b may also include other modules, circuits, devices that do not necessarily form part of the underlying invention per se, e.g. including a pulsing circuit. The functionality of the other modules, circuits, device that do not form part of the underlying invention are known in the art and are not described in detail herein.

Principle of Operation for Pipe Wall Thickness Monitoring

The new pipe wear monitoring system according to the present invention uses a series of conformable ultrasonic transducers that are permanently or semi-permanently mounted around the perimeter of a pipe. These transducers are coupled to an ultrasonic pulser/receiver that sends an electrical signal to the ultrasonic transducer. The ultrasonic transducers convert the electrical signal into a traveling stress wave (ultrasonic wave) that propagates through the pipe wall, reflects from the inner surface of the pipe and returns to the ultrasonic transducer. The ultrasonic transducer then reconverts this returning stress wave into an electrical signal that is amplified and processed by the ultrasonic pulser/receiver. The ultrasonic pulser/receiver then determines the amount of time that it has taken the stress wave to travel from the transducer to the inner surface of the pipe and back to the transducer. Using the well known velocity for these stress waves in the pipe wall material, the thickness of the pipe wall can be accurately determined. This system is designed to measure the thickness of steel walled pipes but can be possibly extended to polymer pipes, depending on the wall thickness and material acoustic properties.

Comparison to Conventional Ultrasonic Thickness Measurement Instrumentation and Techniques

The current or known baseline pipe wall thickness measurement technique consists of a handheld ultrasonic transducer and a portable pulser/receiver. One comparison between the system according to the present invention and a sophisticated handheld ultrasonic pipe wall thickness measurement tool revealed similar results. Measurements taken at the exact same points were not possible since the system according to the present invention was installed before the conventional ultrasonic measurements could be performed. The location difference may be in the axial direction but the circumferential locations were kept the same as shown in FIG. 16.

Small variations between the conventional ultrasonic technique and the system according to the present invention are due to the differences in axial location. The comparison was performed at two different periods of time to ascertain the ability to measure pipe wall thickness trends. The results shown in FIG. 17 reveal that there are some differences in the absolute wall thickness measured but more importantly that there are differences in the trends recorded between the two instruments. The system according to the present invention measured a reduction in wall thickness at all points, which was expected. In contrast, the conventional ultrasonic approach indicated that some measurement points showed no or minimal wear.

Measurement and Visualization of Pipe Wear

The pipe wall thickness measurements can be graphed in a polar plot to provide a visual indication of the wall thickness as a function of the angular distance from a set reference point on the pipe. New software that interpolates between sensor points and provides robustness in the possibility of erroneous data or a failed sensor has been implemented. The hardware, analysis and data management takes into account pipe rotations to monitor wear trends and project to the point in time at which the pipe wall safety margins have been crossed. An example of the visualization of the pipe wall thickness around the pipe is shown in FIG. 18. See also FIG. 29. In the plots, one can see thinner pipe walls at various angular locations around the pipe due to intentional rotations of the pipe performed to increase the pipe lifetime. In other situations, uneven pipe wear will result from changes in the flow profile after elbows or other pipe geometry effects.

Short Term Temperature Effects and Repeatability

This system has undergone testing for repeatability, impact of environmental temperature changes, and the impact of transducer to transducer variability. The results from varying these three factors may be consolidated into a single data set as shown in FIG. 19. An examination of the graph reveals that over 81% of the data is within +/−0.12% or +/−0.013 mm, and all the results are within +/−0.47% or +/−0.05 mm. The repeatability is well within the requirements to determine impending failure due to pipe wall thinning or to reliably track wear rates.

Pipe Wear Trend Monitoring

A demonstration of the ability to monitor and quantify the wear rates in a pipeline has been demonstrated in the field. In FIG. 20, the wear rate in a high wear rate environment shows the rapid decrease of wall thickness over a period of 23 weeks.

Pipe Surface, Thermal Cycling and Long Term Elevated Temperature Effects

It is to be expected that the inside surface of the pipe will have an impact on the strength and form of the reflected ultrasonic signal. Long term effects including temperature cycles and high temperature degradation will also play a role in the reliability of these measurements. Tests are underway to fully understand the impact of these effects. To date, a variety of pipes from steel to chromium-steel with a variety of inner surface topologies have been studied and tested with good results, as verified with caliper measurements. Three of these surfaces are shown in FIG. 21.

Temperature cycling from −40 C to +40 C with 10 hour holds on a semi-permanent style system using ultrasonic gel couplant has been initiated and the results of the first 46 thermal cycles reveals no discernable difference in pipe wall thickness as seen in FIG. 22. In addition, a comparison of the amplitudes of the signals from one of the sensors indicated no degradation in amplitude as seen in FIG. 22. After 46 cycles, the amplitude of the signal increased relative to the initial pulse and the pulse after 6 cycles.

The long term testing at 50C to 70C showed no detectable change in the pipe wall thickness measurement, that is no detectable change in the time from the initiation of the trigger pulse to the detection of the reflected ultrasonic signal. The amplitude of the signal which has a bearing on the reliability of the sensing system and the signal to noise did show some slight degradation of less than 20% amplitude over a period of three months as seen in FIG. 23. A new design has been implemented which is expected to see much lower amplitude changes in the ultrasonic signals during similar long term testing. In addition, a permanent style system which does not use ultrasonic gel couplant is expected to see even smaller changes.

FIGS. 24-28 Other Pipe Wall Thickness Measurement Systems and Improvements

A common problem for pipelines of all types is the potential for corrosion and wear of the pipes inner surfaces over time and the potential for pipeline rupture if the wall becomes too thin. The corrosion or wear in applications such as slurry transport is so severe that in some instances pipes have to be replaced several times a year. In some applications where the wear and corrosion is not uniform (i.e. more wear on the bottom inside of the pipe) the pipes are frequently rotated to even out the wear and increase the overall lifetime of the pipe.

Pipe Wall Thickness Measurement System with Self-Referencing Measurements and Pipe Orientation Correction

Currently, pipeline operators monitor the condition of the walls of their pipes using handheld ultrasonic gauges that must be placed in contact with the pipe for each measurement point. This process has to be repeated for multiple points at the same pipe location since the entire circumferential profile of the pipe is desired. This is a very time consuming and error prone process performed on frequently a large number of measurement locations, sometimes numbering up into the tens of thousands of points. Permanent attachment of the ultrasonic sensors would improve the reliability of the measurements, but this approach is not practical or cost effective particularly in the applications that require frequent pipe rotations or replacement.

The present invention provides a new measurement system that is based on the same basic ultrasonic measurement principle but presents a novel approach that eliminates many of the current problems. The basic sensing transducer is a series of piezoelectric elements (such as PVDF) that are permanently attached to the pipe wall. See FIG. 24. As shown here, the sensors are equally spaced circumferentially around the pipe to provide a complete profile of the wall thickness. However the spacing or number of sensors does not have to be fixed.

Since piezo elements made of materials like PVDF are cheap, the sensor band can be permanently attached providing for very reliable and repeatable measurements. The electronic reading unit can be portable and hand carried to the sensor bands or permanently mounted next to the sensor band, collecting data and storing or relaying the data by wireless or other means to a central gathering station.

Measurement of the wall thickness will be performed by the well known single element pitch-catch method, where the PVDF serves as both the ultrasonic signal transmitter and receiver (alternatively 2 PVDF elements could be used in a dual-transducer approach). An ultrasonic pulse is injected into the pipe by way of the PVDF sensor; the pulse then reflects off the back surface of the pipe wall and is detected by the same PVDF sensor. The amount of time it takes for the received pulse to traverse the pipe wall is proportional to 2 times the wall thickness. However it is often difficult to achieve the required accuracy with this single reflection approach since the electronics must inject a large signal into the pipe and then be sensitive enough to detect rapidly a respectively weak return pulse. This must be accomplished with very precise timing to obtain an accurate thickness measurement.

This disclosure utilizes a self-referencing approach that will greatly improve the accuracy. FIG. 25 shows two implementation. In a), once the pulse is produced it is injected into a spacer and from there it travels to the pipe wall. Once the pulse hits the outer pipe wall an amount will be reflected back, along with the reflection from the inner pipe wall a certain time later. The difference between these two detected pulses is proportional to the wall thickness. In addition, as shown in b), the injected pulse into the pipe wall will continue to bounce back-and-forth producing a series of equally spaced pulses as shown in the data in FIG. 26. To determine the wall thickness the time between successive pulses is measured, eliminating the requirement for absolute timing based on the injected pulse. The received pulses can be detected with a variety of signal processing techniques ranging from simple peak detection to quadrature, homodyne or heterodyne demodulation.

One unique problem arises in applications where the pipes are frequently rotated to equalize the inside wear and prolong the lifetime of the pipe. In these systems the wall thickness data that is obtained is used to try and predict both the rotation schedule of the pipe along with the replacement schedule. In the case of the band sensor system presented here, since only discrete points are measured (not continuously) algorithms will be utilized to interpolate between the sensors to obtain a fully continuous wall thickness prediction. To accurately predict the pipe future condition and somewhat interpolate between sensors, the pipe orientation must be known. This information will be used to calculate variable wear rates at different positions on the pipe due to, for example, heavier materials traveling along the bottom of the pipe and inducing greater wear in that location. The orientation of the pipe can be recorded through relative markings placed on the pipe and band; however this system is prone to recording errors. Instead a system proposed here utilizes simple and cheap 2D orientation sensors to automatically record and orient the data. 2 or 3 of these sensors spaced along the band and around the pipe will be able to accurately provide orientation data. Multiple sensors will allow refinement of the semi-accurate data provided by the cheap sensors to pinpoint the orientation.

The system described here represents a cheap way to quickly obtain reliable pipe wall thickness data. The sensor band is optimized on low cost so that it can be permanently attached to the pipe and thrown away when the pipe is worn out. It is a low profile device that can be placed under insulation or other pipe coverings and rotated with the pipe in applications where pipe rotation is required.

The wall thickness and pipe orientation data provided by the system can greatly optimize the operation of pipelines both in the respects of minimizing pipe ruptures as well as helping to prolong the lifetime of the pipes through optimization of pipe rotation and replacement.

Pipe Wall Thickness Measurements with Large Area Sensors

When measuring pipe wall thickness with traditional ultrasonic transducers, the system can often be confused when small area defects or pits are present in the pipe wall. This condition can often be found in specialty lined pipes that are used in harsh wear environments. Fedur and chromium-lined pipes are typical examples. In the case of chromium lines pipes, a standard carbon-steel pipe is taken and a bead of chromium is welded in a spiral fashion inside the standard pipe, providing a solid inlay. This pipe demonstrates improved wear characteristics; however the welding process will create a large number of small voids, bubbles and defects at the interface layer between the chromium and the outer carbon-steel. When a wall thickness measurement is made on this pipe the defects and voids will reflect the ultrasonic energy that strikes them, potentially giving a false thickness measurement. FIG. 27a ) shows a diagram of how this may occur. The smaller focused beam of the traditional ultrasonic sensors may hit a defect or a small cluster of defects and reflect back enough energy to give a false reading. Often times the transducer can be slightly moved to clear the small obstruction, but an operator will not know this needs to be done.

The present invention provides an advantage of a PVDF based pipe wall thickness measurement that helps to remedy this problem. This can be accomplished since a PVDF ultrasonic sensor can be fashioned easily in a variety of shapes and sizes. For typical inlayed pipe the small defects are present at the interface between the two layers in a relatively even distribution, however the majority of the interface area is clear of defects. By using a PFDV sensor which is spread out over a large area, a large area ultrasonic beam is introduced into the pipe wall. The defects will reflect back a portion of the ultrasonics signal, however a large portion of the signal will still travel through and be reflected back by the true pipe inner wall. The received signal will exhibit a small amplitude when the defect reflected signal are detected, however a large signal will be observed from the inner pipe wall. Now, both the amount of defects can be seen along with the true inner pipe wall thickness.

Several methods can be used to process the resulting signals to discern the defect signals from the inner wall signals. The most telling signal is simply the amplitude. Since the defects are plentiful in a typical lined pipe however do not cover the majority of the area they will give a smaller reflected profile.

Permanent Pipe Wall Monitoring System with Disposable Sensor Elements

Current pipe wall thickness measurements are performed with hand held thickness transducers and electronics. This requires a manual attachment of the sensor transducer to the pipe each time a measurement is desired, resulting poor repeatability and accuracy. The quality of the data obtained is very dependent on the skill, training and experience of the operator. They system described here replaces the manual pipe wall thickness measurements with a permanently mounted system that will improve repeatability and accuracy.

In its simplest form the sensor head consists of a ring of multiple sensors that are permanently attached to the outside of the pipe to be measured. FIG. 28a shows a configuration here the light areas represent the actual sensors.

To achieve the low cost and flexibility required a piezoelectric (PZT) material PVDF is used for the sensors. Since PVDF is not as sensitive as the traditional PZT materials for wall thickness measurements it is important that the PVDF sensors be placed in as close a contact with the pipe wall as possible. In FIG. 28b a samples and construction is shown, this construction has the advantage of protecting the sensitive PVDF material while also providing the best ultrasonic signal pathway from the sensor to the pipe wall. In this example, a rugged band is used to compress the sensors onto the outside of the pipe. This band can be made of metal which will impart a compressive force to maintain contact between the sensors and the pipe while also providing the environmental protection. Under the band a piece of compliant material (such as rubber) is attached at the sensor locations. This compliant material is used to cushion the PVDF but to also allow the PVDF to conform to the shape of the surface of the pipe. Since the outer surface of the pipe may contain ridges or steps in its surface it is advantageous to force the PVDF to conform to the shape as much as possible. This will maximize the amount of signal the sensor will receive from the pipe wall and improve overall system performance. Under the sensor a couplant is used to help transfer the ultrasonic energy from the sensor to the pipe and vice versa during the measurement. This couplant can take the form of a solid gel, a liquid gel or a combination of the two. The goal of the gel is to eliminate all air pockets on the pipe surface and maximize the ultrasonic signal path between the sensors and the pipe wall. The liquid gel will serve to fill the voids, however often the gel will dry out over time. The solid gel typically will not be able to get down into all the voids. However, a combination of the two with the liquid gel in the smallest voids, covered over by the solid gel should provide a good long lasting ultrasonic path.

FIG. 29: Measurement and Visualization of Pipe Wear

As shown in FIG. 29, and consistent with that described above, the pipe wall thickness measurements can be graphed in a polar plot to provide a visual indication of the wall thickness as a function of the angular distance from the top of the pipe. A set of representative plots from data taken at a customer site clearly shows high wear rates on the pipes as seen in FIG. 29. The degree of wear is unequivocally seen. In the plot shown in FIG. 29a the high wear rate is on the bottom of the pipe as expected in a stratified (non-homogeneous) flow situation. In FIG. 29b , the high wear rate appears to be on the top of the pipe due to an intentional rotation of the pipe performed to increase pipe lifetimes. In other situations, uneven pipe wear will result from changes in the flow profile after elbows or other pipe geometry effects.

FIGS. 30-32: Pipe Wall Thickness Interpolation and Wear Extrapolation

The system according to the present invention is designed to be permanently attached to a pipe and provide, e.g., 12 discrete pipe wall thickness measurements, although the scope of the invention is not intended to be limited to any specific number of sensors or measurements. Since the sensors are permanently attached the system provides a very reliable and repeatable thickness measurement in the exact same location. In addition, the 12 sensors are equally spaced circumferentially around the pipe. The combination of the high quality measurements and spatial placement permits insight into additional information on the condition of the pipe as well as accurate predictions into the future pipe wear.

FIG. 30 shows an example of the 12 circumferential points. Several methods can be used to interpolate in between the individual 12 measured pipe wall thicknesses. Cubic spline or polynomial regression techniques are two examples of curve fitting routines that can provide interpolated points. However, due to the periodic and repeating nature of the equally spaced points measured around the circumference of the pipe, a Fourier decomposition based interpolation is ideal. This technique calculates the various Fourier components required to create a curve which includes all the sample points. Once the equation of the curve is known that includes the 12 measured points the intermediate locations between the points can be calculated. Using this interpolation the minimum wall thickness can be found, even if the minimum thickness point is between the actual measured locations. An additional benefit of this analysis is that erroneous sensor readings can potentially be identified. A sensor reading that is far off will either not permit the Fourier decomposition to converge on a solution, or will require an excessively large high frequency component. By limiting the magnitudes of the various derived Fourier components to physically realistic values points that cannot be described with the derived Fourier components can be flagged as potential erroneous points. In addition, custom tailored weighting coefficients can be used on the Fourier components depending on the particular situation. FIG. 31 shows a situation where a measured wall thickness cannot be described by a set of limited Fourier components. Here the wall thickness (y-axis) versus degree rotation (x-axis) around the pipes is shown. The squares represent the measured values and the line the interpolated numbers. In this particular situation the highest frequency component would have been the largest component if the Fourier decomposition was allowed to fit to all points. By limiting the magnitude of this component the point at 180 degrees is identified and discarded from the data set.

In addition to interpolation between the measured points of the wall thickness, analysis can be used to predict the future condition of the pipe. From the frequent accumulation of data and the accuracy of the data, extrapolation techniques can be used to model and predict the future pipe wear. FIG. 32 shows an example of a calculated wear model for a pipe. Several techniques can be used to derive the wear profile and extrapolate the future pipe wall thickness including least-square polynomial extrapolation and Fourier component extrapolation. The scope of the invention is not intended to be limited to any particular type or kind of extrapolation technique, and embodiments are envisioned using other types or kinds of extrapolation techniques either now known or later developed in the future.

The techniques described here permit additional pipe information to be obtained from the measurement of pipe wall thickness using the present technology. Whole pipe interpolation permits the monitoring of pipe wall thicknesses throughout the full circumference of the pipe with only 12 actual measurements. In addition, future pipe condition can be extrapolated by calculating a wear profile and determining the ideal lifetime or rotation schedules for the pipe to optimize the pipe viable life. The model can help determine when a pipe should be rotated and at which angles in an effort to equally distribute the pipe wear around the pipe inner wall. Also trigger points can be established such that the model will predict certain wall thickness configurations requiring intervention from maintenance personnel.

FIG. 33: Adaptive Frequency Tuning for Pipe Wall Thickness Measurements

The measurement of material thicknesses using ultrasonic techniques is well known. The most prevalent method involves a simple pulse-receive time based approach that measures the amount of time it takes for an ultrasonic pulse to traverse the material thickness. Often this measurement is performed with the ultrasonic transmitter & receiver located essentially in the same location. Therefore the ultrasonic pulse must travel through the material, bounce off the opposite side and then return to be detected. Along the path the ultrasonic signal must travel, several mechanisms can attenuate the signal and possible severely degrade the measurement or prevent a measurement from being taken. This disclosure discussed a technique to aid in the maximization of the signal received as well as a means for continuously maintaining the signal integrity.

As the ultrasonic signal traverses through the material under test and reflects off the opposing side it is subject to several mechanisms including attenuation of the material and surface interferences from the reflecting side. FIG. 33 shows a diagram of the path of the ultrasonic signal through the material and these two key attenuation mechanisms. These two key items can be potentially minimized significantly by tuning the frequency of the ultrasonic pulse used to probe the material.

The attenuation of acoustic waves varies with frequency and often can exhibit large variations with the doubling or tripling of the frequency; therefore by simply optimizing the ultrasonic frequency large gains in resultant signals amplitude can be achieved. With traditional ultrasonic transducers based on ceramic piezoelectric elements the tuning frequency is often very limited. These materials typically exhibit a sharp resonance peak and their efficiency quickly drops off once they are de-tuned. PVDF and some other materials however exhibit more of a broad-band response. These materials are much more conducive to frequency tuning and laboratory testing has demonstrated that they can indeed be frequency tuned to minimize the effects of the subject materials attenuation characteristics.

The reflection of the ultrasonic signal off the opposing wall of the material as shown in FIG. 33 imposes two mechanisms that effect the quality of the signal reaching the ultrasonic receiver. First, irregularities in the signal will cause portions of the injected signal to reflect off in different angles, reducing the returned signal. In addition, since the surface of the inner wall can vary within the area of the ultrasonic signals portions of the signal will travel slightly different distances when it recombines at the sensor. This can result in interference of the signal with itself, and in the case of destructive interference will reduce the measured signal. The frequency of the ultrasonic signal can vary both of these effects and can be used to minimize their effects. As an example, in general a lower frequency signal (and therefore a longer wavelength) will not be as susceptible to small surface variations in relation to the signal wavelength.

In addition, with an adjustable frequency of the ultrasonic signal advanced signal processing techniques can be utilized to reduce the signal-to-noise of the detected signal. Synchronous detection of a phase or frequency encoded radio signal has been used extensively to improve radio reception. These same techniques can be utilized to improve the signal integrity of the ultrasonic signals. By modulating the phase of the ultrasonic signal with, for example, an m-sequence code, a demodulator on the receive side could correlate with the known code and be able to detect the desired signal from system noise and other non-coherent reflections.

FIG. 34: The Orientation or Rotation Sensor

FIG. 34 shows an embodiment generally indicated as 200 of the apparatus or system of the present invention in which one or more orientation or rotation sensors 202 a, 202 b is integrated along with the multiple wall thickness measurements indicated as 204 a, 204 b, 204 c, . . . , 204 k, 204 l into a sensor band 206. The orientation or rotation sensors 202 is shown as a device having an orientation sensor housing and electronics that is arranged in the sensor band 206 in relation to the multiple wall thickness measurements 204 a, 204 b, 204 c, . . . , 204 k, 204 l. As shown, the sensor band 206 has two orientation or rotation sensors 202 a, 202 b, one arranged at the top 202 a, and one arranged at the bottom 202 b, although the scope of the invention is not intended to be limited to the number or angular position of the same in the sensor band 206. As a person skilled in the art would appreciate, when the wall thickness measurements 204 a, 204 b, 204 c, . . . , 204 k, 204 l are arranged circumferentially equi-distantly about the sensor band 206 in relation to the one or more orientation or rotation sensors 202 a, 202 b, then the orientation of each wall thickness measurements 204 a, 204 b, 204 c, . . . , 204 k, 204 l may be determined based on the orientation the one or more orientation or rotation sensors 202 a, 202 b. The orientation is understood to be in terms of the angular position of the orientation or rotation sensor from 0 to 360 degrees about the circumference of the pipe. In operation, each orientation or rotation sensor 202 a, 202 b responds to its orientation after the sensor band 206 is arranged on the pipe (not shown), and provides an orientation signal containing information about its angular position about the pipe, e.g., back to the one or more modules 102 a.

One problem that the customer faces is that they do not have an accurate tracking of the pipe orientation along with the wall thickness data. With the integration of the orientation or rotation sensor 202 a, 202 b, one now will know the current pipe orientation along with very repeatable thickness measurements. This allows the technique according to the present invention to not only report this to the customer, but opens up the possibility of enhanced future pipe predictive behavior.

As an example for a very striated flow in the pipe (i.e. where the heavy sand and rock laden material is flowing along the bottom of the pipe, relative to the water rich portion at the top), the technique according to the present invention can estimate the pipe wear rate at the top versus the bottom. The technique according to the present invention can then may predict the lifetime of the pipe and optimize customer pipe rotation schedules. The orientation rotation or sensor 202 a, 202 b is the key here since it will provide the orientation (i.e. which is at the bottom subject to the high wear).

Orientation rotation or sensors are known in the art; and the scope of the invention is not intended to be limited to any particular type or kind thereof either now known or later developed in the future. By way of example, one known orientation rotation or sensor that has been used takes the form of a gravity-based device that is configured to respond to its orientation, and provides an orientation signal containing information about its angular position.

III. Conclusion

Existing sonar-based flow measurement technology has been extended to two new applications. It has been demonstrated that a sonar-based meter is able to measure the velocity profile in a horizontal slurry line in real-time. Measured changes in the velocity profile show the ability to detect different flow regimes: both homogeneous and heterogeneous flow with fully suspended solid particles, and flow with a stationary bed. The ability to detect a stationary bed was confirmed by separate measurements of density across the bottom of the pipe and differential pressure across the velocity profile meter. One potential benefit of this measurement for hydro transport line operation is reduction of water and energy usage by operating at higher solids concentration and/or lower velocities while avoiding problems and costs due to solids deposition.

The ability to reliably, accurately, and cost effectively provide pipe wall thickness measurements in a timely manner has been demonstrated. The repeatability over a variety of operating conditions including sensor to sensor variation, temperature ranges, and time has been clearly shown in both laboratory and field tests. This technology is easily extended into monitoring of most structures found in a pipeline including elbows, valves, and many others. The resulting cost savings for both the pipe inspections and production savings through enhanced production up-time can be quite large. Most importantly, the potential impact on personnel safety and environmental savings will be enormous.

The Scope of the Invention

While the invention has been described with reference to an exemplary embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, may modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment(s) disclosed herein as the best mode contemplated for carrying out this invention. 

What is claimed is:
 1. A method for monitoring the thickness of a wall of a pump casing for a pump used for pumping an abrasive fluid or slurry, comprising: injecting an ultrasonic-based transducer pulse from a discrete ultrasonic-based transducer attached to a pump casing of a pump at a local point of interest; sensing with the discrete ultrasonic-based transducer the ultrasonic-based transducer pulse reflected off a wall of the pump casing at the local point of interest; receiving with an electronic monitoring system a signal containing information about the ultrasonic-based transducer pulse sensed; and determining with the electronic monitoring system the thickness of the wall of the pump casing at the local point of interest based at least partly on the signal received.
 2. A method according to claim 1, wherein the method comprises directly attaching the discrete ultrasonic-based transducer on the pump casing at the local point of interest.
 3. A method according to claim 1, wherein the method comprises receiving a plurality of signals from a respective plurality of discrete ultrasonic-based piezoelectric transducers, each discrete ultrasonic-based piezoelectric transducer attached directly on the pump casing at a respective local point of interest on the pump casing of the pump.
 4. A method according to claim 1, wherein the discrete ultrasonic-based transducer is housed in a lightweight, low profile, small footprint package so as to be positionable into a tight space and into a local area for measurement, including the lightweight, low profile, small footprint package being dimensioned to include a length of about 3″, a width of about 1.5″ and a height of about 0.8″.
 5. A method according to claim 2, wherein the step of directly attaching comprises coupling the discrete ultrasonic-based transducer to iron components by high-strength permanent magnets and a suitable ultrasonic coupling gel, which allows easy installation, removal and repositioning of the discrete ultrasonic-based transducer, and also allows the discrete ultrasonic-based transducer to be adjusted to maximize signal strength and quickly redeployed to other wear points of interest.
 6. A method according to claim 1, wherein the step of directly attaching comprises coupling the discrete ultrasonic-based transducer to a substrate using a pressure sensitive adhesive or a dispensable adhesive.
 7. A method according to claim 1, wherein the discrete ultrasonic-based transducer comprises a discrete ultrasonic-based piezoelectric transducer made at least partly from PVDF material.
 8. A method according to claim 1, wherein the method comprises providing with the electronic monitoring system an indication containing information about the thickness of the wall of the pump casing at the local point of interest, including an output signal, an audio indication, a visual indication, or some combination thereof.
 9. A system for monitoring the thickness of a wall of a pump casing for a pump used for pumping an abrasive fluids and slurry, comprising: a pump having a pump casing with a wall; a plurality of discrete ultrasonic-based transducers; an electronic monitoring system; and a wiring harness for coupling the plurality of discrete ultrasonic-based transducers to the electronic monitoring system; each of the plurality of discrete ultrasonic-based transducers configured to attach directly on the pump casing at a respective local point of interest of the pump casing of the pump, inject a respective ultrasonic-based transducer pulse into the pump casing at a respective local point of interest, sense the respective ultrasonic-based transducer pulse reflected off a wall of the pump casing at the respective local point of interest, and provide a respective signal containing information about the respective ultrasonic-based transducer pulse reflected off the wall of the pump casing at the respective local point of interest; the electronic monitoring system configured to receive respective signals from the plurality of discrete ultrasonic-based transducers, and determine the thickness of the wall of the pump casing at the respective local points of interest based at least partly on the respective signals received.
 10. A system according to claim 9, wherein each discrete ultrasonic-based transducer is housed in a lightweight, low profile, small footprint package so as to be positionable into a tight space and into a local area for measurement, including the lightweight, low profile, small footprint package being dimensioned to include a length of about 3″, a width of about 1.5″ and a height of about 0.8″.
 11. A system according to claim 9, wherein the system comprises high-strength permanent magnets and a suitable ultrasonic coupling gel for coupling the discrete ultrasonic-based transducer to iron components so as to allow easy installation, removal and repositioning of the discrete ultrasonic-based transducer, and also allow the discrete ultrasonic-based transducer to be adjusted to maximize signal strength and quickly redeployed to other wear points of interest.
 12. A system according to claim 9, wherein the system comprises a pressure sensitive adhesive or a dispensable adhesive for coupling the discrete ultrasonic-based transducer to a substrate.
 13. A system according to claim 9, wherein the discrete ultrasonic-based transducer comprises a discrete ultrasonic-based piezoelectric transducer made at least partly from PVDF material.
 14. A system according to claim 9, wherein the electronic monitoring system is configured to provide an indication containing information about the thickness of the wall of the pump casing at the local point of interest, including an output signal, an audio indication, a visual indication, or some combination thereof.
 15. Apparatus comprising: a signal processor configured to: receive a signal containing information about a discrete ultrasonic-based transducer pulse that is injected by a discrete ultrasonic-based transducer attached directly to a discrete location of a pump casing and sensed by the discrete ultrasonic-based transducer after being reflected off a surface of a wall of the pump casing; and determine corresponding signaling containing information about the thickness of the wall of the pump casing at the discrete location based at least partly on the signal received.
 16. Apparatus according to claim 15, wherein the signal processor forms part of an electronic monitoring system configured to monitor the thickness of the wall of the pump casing at the discrete location, including providing an indication, in the form of an output signal, an audio indication, a visual indication, or some combination thereof, containing information about the thickness of the wall of the pump casing at the local point of interest.
 17. Apparatus according to claim 16, wherein the discrete ultrasonic-based transducer comprises a discrete ultrasonic-based piezoelectric transducer that is configured to inject a discrete ultrasonic-based piezoelectric transducer pulse at the discrete location of the pump casing, and sense by the discrete ultrasonic-based piezoelectric transducer pulse reflected off the surface of the wall of the pump casing.
 18. Apparatus according to claim 15, wherein the signal processor is configured to provide the corresponding signal containing information about the thickness of the wall of the pump casing at the discrete location.
 19. Apparatus according to claim 18, wherein the apparatus comprises an ultrasonic pulser/receiver having the signal processor configured therein.
 20. Apparatus comprising: means for receiving a signal containing information about a discrete ultrasonic-based transducer pulse that is injected by a discrete ultrasonic-based transducer attached directly to a discrete location of a pump casing and sensed by the discrete ultrasonic-based transducer after being reflected off a surface of a wall of the pump casing; and means for determining the thickness of the wall of the pump casing at the discrete location based at least partly on the signal received.
 21. Apparatus according to claim 20, where the apparatus further comprises means for providing an indication, in the form of an output signal, an audio indication, a visual indication, or some combination thereof, containing information about the thickness of the wall of the pump casing at the local point of interest. 